Education - Teacher headcount in State and State Integrated Schools, by age group 2004–2023

Includes all teachers, both regular (permanent and fixed term) and day relief teachers.
Teachers can work in more than one role across a year. Here teachers are counted in their main role, which is the role that they worked the most hours in during the year.
The age of the teacher, in ten year age-groups. Age is calculated as at 1 July for each year.

Teacher: Employee on a teaching agreement and received at least one ‘normal’ salary payment for the year. Teachers who work in multiple roles are reported against the role in which they worked the most hours during the year.
Main teacher role: The main teacher role is defined as the role where the employee worked the most full-time teacher equivalents (FTTEs) during the entire year as a teacher

https://www.educationcounts.govt.nz/data-services/data-collections/national/schooling-workforce

All types of teachers are included - fixed term, permanent and day relief staff.

In 2018, the Ministry of Education developed a new data series for the schooling workforce. This is based on a calendar year, rather than a point in time (single pay run) as occurs with the old measure (which was based on the first pay run in April) The new data series therefore includes a greater number of teachers.
The new data series covers a twelve month period with the start of the year being the first pay period that is fully within January.
The new schooling workforce data series includes composite schools in the secondary sector.

At URL provided, select 'Time Series: All Teachers Headcount 2004-2023' from under the 'Teacher Headcount: Time Series Data' heading.

This data series presents demographic information on teachers in state and state integrated schools and covers a twelve month period with the start of the year being the first pay period that is fully within January.

The size of the teaching workforce can be measured either as a headcount or in terms of full-time teacher equivalents (FTTE). FTTE data are only available from 2014 onwards - data from previous years are not comparable due to changes in definitions.